How important is it to have your dirt bath in the sun please?

Hello.

I'm new to planning my chicken space, and I'm putting some thought into their dirt bath. Can someone please share their thoughts on how important it is to have the dirt bath in the sun, or is this not important at all?

I'm looking at maximising the space we have and thinking of making a two level sturdy platform. The ground level would be used for shade, the first level is used for their dirt bath and the second for growing a grazing frame. Is this a crazy idea or could you see this type of structure working if it was done properly?

Thank you so much for your responses.